"I just had short temper but being a sergeant in the Marine corps, it's kind of that expectation that are you doing your job well when you are kind of on that edge a little bit," he said. "The problem was carrying that home."

The U.S. Department of Veterans Affairs reports that almost 20 percent of veterans suffer from PTSD. But many patients say it can be difficult to seek help.

That's where people like Suzi Landolphi come in. She leads the equine-assisted therapy program at Boulder Crest Retreat and says veterans can learn to manage stress and begin to feel at peace through walking and grooming the animals.

"When you have gone through traumas you have to put up defenses. So you have to find a way to deal," Landolphi said. "It's not always helpful to yourself. You think it is, but it's not. What the horses offer is an opportunity to let down all your defenses."